I'm also extremely curious as to how and why Outfox works as it does.
My best understanding is that Outfox is just a proxy, with a focus on low latency and geographic server diversity. Theoretically, it should work for any game, even peer-to-peer games like Destiny 2 and Call of Duty.
I guess another poster made a good point that GoldenFrog doesn't want you to abuse their servers and use them for streaming, downloading files, browsing the web, etc. I'm guessing there are also privacy concerns, since OutFox proxies aren't encrypted like a typical VPN?
Nonetheless, I wish and hope GoldenFrog will offer some sort of solution for console gamers in the future. I've already used their non-gaming VyprVPN service through my DD-WRT router and played PS4 games on that, but the lag was pretty bad.